Church Sound and Video Advice > Audio Tips > Computer Sound

How should we connect the sound from our computer to our mixer?

Local Computer

If your computer and mixer are within 10 or 15 feet of each other, this would be considered local. In this case you can connect the computer sound output into the mixer line input. If you are also connecting the computer video to a projector however, this will probably create a ground loop which results in AC hum in the sound. If so, you will need to add a ground decoupler between the computer and mixer. The diagram below shows how.

Assuming you already have the mic jack installed and wired to your mixer, and the computer video connected to the projector, here is what you need to accomplish this:

1) Decoupler box such as the AGDC2

1) Mini Phone to 1/4" Phone cable such as the ASITSM (from computer to Decoupler Box)

1) 1/4" Phone cable such as ASITRS (from Decoupler Box to Line input on mixer)

NOTE: For stereo sound you will need an AGDC2, two ASITRS cables and an A505 and two A256G adapters.

Remote Computer

If your computer is located more than 15 feet from the mixer, you should not use the line input on the mixer. Because the output from the computer is unbalanced, it is likely to pick up radio, and AC interference when run more than 15 feet. Instead you need to convert it to a balanced signal (at the computer end) and fed this to a balanced microphone input on the mixer.

This is accomplished by using a DI box and the appropriate cables. Since the DI box has a ground lift switch, it will also eliminate the ground loop between the computer and mixer (and projector). A ground loop causes AC hum in the sound. See the diagram below.

Assuming you already have the mic jack installed and wired to your mixer, and the computer video connected to the projector, here is what you need to accomplish this:

1) DI box such as the DB25

1) Mini Phone to 1/4" Phone cable such as the ASITSM (from computer to DI Box)

1) Balance XLR Mic Cable such as C25XXC4 (from DI Box to Mic Jack or to mixer)

NOTE: For stereo sound you will need two C25XXC4 cables, two DB25 boxes and an an A505 and two A256G adapters.